Group therapy is frequently used in clinical settings for the treatment of substance abuse in adults and adolescents. Unfortunately, research evidence is generally lacking on the efficacy of group treatments for substance abuse in adolescent populations. Specifically, there is very little research on the efficacy of group substance abuse treatments for adolescents from minority backgrounds. The Hispanic population currently accounts for approximately 12% of the national population; however, it is expected that the population of Hispanics will grow to 24% of the national population by the year 2050. Many researchers have argued for the need of substance abuse treatments which are culturally relevant for specific minority populations. Therefore, one area that requires more research attention is the efficacy of group therapies for substance abusing Hispanic adolescents. The proposed research plan is a part of a 5-year Mentored Patient-Oriented Research Career Development Award (K23) for Dr. Jason Burrow-Sanchez. The proposed research will be conducted in two studies consistent with stage model methodology. In Study 1, a group based standardized cognitive-behavioral treatment (SCBT) will be adapted to a culturally relevant Hispanic version treatment (HVT) for substance abusing Hispanic adolescents. The HVT will then be compared with the SCBT in a pilot study with Hispanic adolescents. In Study 2, a randomized clinical trial of the HVT and SCBT with a larger sample of Hispanic adolescents will be conducted. It is predicted that Hispanic adolescents in the HVT condition will demonstrate better post treatment outcomes (e.g., reduced level of drug use) compared to Hispanic adolescents in the SCBT condition. RELEVANCE OF THE RESEARCH TO PUBLIC HEALTH: Research on the cultural adaptation of cognitive- behavioral group treatments for Hispanic adolescents with substance abuse problems is lacking. The proposed research will provide needed information in this area by testing a culturally adapted substance abuse group treatment for Hispanic adolescents.